Jen. 1908] Cultures of Uredineae in igoy 



98 ^ 



D. House, Clemson College, S. C, J. J. Davis, Racine, Wis., T. 

 D. A. Cockerell, Boulder, Colo., D. Reddick, Ithaca, N. Y., R. 

 J. Pool, Lincoln, Neb., E. W. Olive, Madison, Wis., F. L. Stev- 

 ens, West Raleigh, N. C, C. F. Baker, Santiago de la Vegas, 

 Cuba, and Geo. W. Carver, Tuskegee, Ala. Host plants suitable 

 to grow in pots and be used for inoculation were contributed by 

 C. S. Sargent, Jamaica Plains, Mass., E. Bethel, Denver, Colo., 

 and J. J. Davis, Racine, Wis. For these favors, and for the 

 hearty co-operation of the above and other correspondents most 

 grateful acknowledgment is here extended. 



During the present season 98 collections of material with 

 resting spores and 20 collections with active spores were em- 

 ployed, from which 438 drop cultures were made to test the 

 germinating condition of the spores. Out of the 98 collections 

 with resting spores 29 could not be brought to germination, 

 although seemingly in perfectly healthy condition. This left 68 

 collections of available material, with which the cultures were 

 made. These 68 collections belonged to 47 species of rusts, a 

 considerable part, however, being forms whose life cycle had 

 already been ascertained, the sowings being made for purposes 

 of verification or extending the range of hosts. Beside these 

 collections of resting spores sowings were made of nine species 

 of Gymnosporangium, and of a few species of Coleosporium, 

 Aecidium and Peridermium. Altogether 296 sowings were made, 

 employing for the purpose 113 species of hosts, and more than 

 two and a half times that number of individual plants, all grown 

 temporarily in pots, so that the work could be done in the green- 

 house under perfect control. In a few cases where small potted 

 plants were not available cuttings were used, being kept alive by 

 frequently changing the water in which they were thrust, and 

 successively cutting off a bit of the stem to give fresh absorbing 

 surface. The results of this work are given in the following par- 

 agraphs, and are divided into negative results, positive results 

 with species whose life cycles have already been ascertained by 

 the writer or other investigators, and positive results with species 

 whose life cycles are now first placed on record. 



Of the trials giving negative results the following may be 

 recorded to serve for reference in future studies : 



1. Puccinia on Carex Pennsylvanica Lam., collected at 

 Sargent, Neb., by Rev. J. M. Bates, was sown on Aesculus gla- 

 bra, Napaea dioica, and Symphoricarpus racemosus. Another 

 collection made near Lafayette, Ind., by Mr. Frank Vasku, was 



sown on Anemonclla thalictroides. Ranunculus septentrionalis, 

 Solidago Canadensis, Viola striata, and Trillium recurvation. 



